Process of producing sulphur and fertilizers



2,416,66rsl mm f jee Greger.

Feb. 25, 1947. A. B. MENEFEE l-:TAL

PROCESS 0F PRODUCING SULPHUR AND FERTILIZERS A original Filed Apri-1 2e, 1941 particles.

` ride and the like.

particularly sulphuric acid v'of 98% strength, is in Patented Feb. 25, 1947 PROCESS F PRODUCING SULPHUR .FERTILIzERs AND Arthur B. Menefee, Cumberstone, Md., and Herbert H. Gregor, Washington, D. C.

Original application April 26, 1941, Serial N0.V 390,622. Divided and this application December 18, 1941, Serial No. 423,544

9 claims. (onze-224).

This invention relates to thev processing of, sulphur-containing materials to produce brimstone l sulphur and other valuableA products. This application is a division' of1prior application Serial No. 390,622, filed April 26, 1941.

It has beeny discovered that sulphur which is associated With organic and inorganic impurities may be separated from such impurities yby a i unique method. As explained fullyin copending applications SerialfNos.^382,844 and 332,845, led March 11,.'1941, thismethod essentially involves heating the sulphur-containing material,` such as an ore or concentrate, in contact witha wetting agent which preferentially wets the non-sulphur `As pointedou't in application, Serial No. 382,845, when a; suitable reagent is utilized and employed inthe properlratio.- to theggangue, or non-sulphur material, and the mass is agitated under the proper conditions, it is possibleto liquefy the sulphur, iiocculate f the gangue and' to cohere the iioccules into larger agglomerates of high mechanical strength andsubstantially unil form size of the order of from l/i to about lAginch in diameter. As explainedinsuch prior` applications and in copending application Serial No. 384,508, iiled March,2119,41,;when conditions Aare properly controlled so as-to produce agglomerates of optimum size, the -moltemsulphur not only flows. freely from theHV gglomerated gangue .but

the gangue agglomeratesthemselves also serveas a particularly eiective `iiltering mediumso that,

the agglomerates function as` a continuously renewing iiltering bedwhich filters out the dispersed smaller gangue particles. Y

As explained in the copending applications referred to, the wetting or agglomerating agent may consist of any material vwhich is insoluble in molten sulphur, which 'preferentially wets and agglomerates the gangue anidlwhich'can be retained in liquid phase under the conditions of the operation. Among such agents are sulphuric and phosphoric acids, hydrated salts, such as cal'- cium chloride, magnesium chloride, Zinc' chlo- Ofithese sulphuric acid, and

many circumstances the preferredvreagent not only because of its eiiicacy as an agglom'eratinar medium but also because itfdecolorizes the sulphur.

As explained in fthe copending applications referred to, the molten'sulphur phase may be sepf arated from theagglomeratephase by anuinber Vof different methods, as for l example simple draining on a screen, as `vexplained in copending application'Serifal No.'382,845. yThis separation may also be effected rapidly by means'of a' continuous centrifuge as explainedin the copending application Se1'ialNo.390,623, filed April 26, 1941'.

In further study'oiy this novel system it has been found thatfthe principle 'ofewettingthe lnonl presence ofrmoltenlsulphur containingan inorga'nic impurity, such as opalescent silica, prefermolten sulphur.

, Vsulphur particles may be invoked to the extentof f utilizing other speciiic wettingagents such as organic liquids.` It is further found that during the extraction and/or decolorizing of sulphur it is possible to utilize this principle of agglomeration while achieving otheradvantages, as -for example by producing a residue of agglomerates "which have Va technical value.

In order more clearly to explain thev invention there is shown in Vthe.xs/tccompainyingidrawings a diagrammatic -illustration of anv apparatus in which it may be carried out in which FigureI is ra ow sheet of a typical .unit and Figure II.,is a

sectional vieWoi the separator employed.`

In the copendingapplications referred to, the

' preferred agglomerating agents mentionedcomprised solutions .of mineralacids and hydrated salts. In furtherV experimentation 'iti' has.. been discovered that theibroad ideaof extracting sulphurby agglomeration of thenon-sulphur material maybe operated utilizing other agglomerated materials, more particularly organic materials. 1 f

It hasy been establishedthat molten sulphur,

'at temperatures below the viscous range, i. e. 320

F., will reactwith only a predetermined quantity of organic materials, such as oils. Testscarried out in which mineral.oil'wascontacted with puri- --ed molten -sulphur at such 'elevated .temperature demonstrated that the sulphur picks up only ap- `proximately0.2% offsuch oil. Thisamount dis- 4colorsthe sulphur but such sulphur may readily be n decolorized in any suitable manner,` as for example by the method described in copending application Serial No. 384,508. The fact'that molten sulphur picks up such minimal quantities of an organic presents Athe definite possibility oi utilizing organics as agglomerating media for lv the main `separation of 4sulphur from associated impurities. It lhas been found thaty an oilinthe entially wets the silic a/and is not wetted by the This nding that"certain organic substances which do notreact to any substantial degree with molten sulphur have'the power of preferentially `wetting the non-sulphur material, establishes the possibility of 'utilizing suchmaterials inthe unique j agglomeration method Ijof separating sulphur. 4The commercial eicacyof suchk a method is inl dicated the following test:

V,Example =Onehundred pounds of puriiied sulphurwas meltedin a steam jacketed kettle-and 'to the fifi molten mass there Was .added three pounds Aoi? reclaimed" siliceous gangue `of mesh; This 'gangue had 4been separated as agglomeratesi4 in 1 gangue were agitated with al@ l Lightnin mixer.

. silica gangue was rather soft. agitator theV oil-collected material rose togthe surface of `the mix. Thereupon an 1.25 pounds of gangue Was added (total of'-4.25 pounds) and the f-"fo'r ashort pe'rio'd. The agglomerates :of #from {l1/s4 'to ,slazinch 'in diameter were -form'ed Afrom fw'hich jthe `Vmolten lsulphur sian 28 mesh screen. '.IIhie 'separated sulphur *was *filtered through'rock Wool 'and Vthe filtrate re- 1 Icovered was of a'good color. fAs a lresult of lthis and determined that sulphur couldzbeseparated from l 'associatedimpur'ities foysagglomerating these im- 1 purties v fleeting 4agents ras cation Serial No..384,508`.

silicates ,and .the like.

@acti-ve collectors, it Willibe acid Which is addedmu'st not only be ithe treatment fChile'an concentrates in`""accord ance Withthe'processldescribed copending application Serial No. 382,845. The reclaimed l gangue had been heated to drive off the sulphuric acid and sulphur.

H. P. 1700 R. P. M.

1.75 pounds of a medium motor cylinderparaf'- nic oil (Booster motor oil) The lIn'aSs W-as agitated for ten minutes during On .stopping the material was further agitated similar tests Tit .Was

Witlrorganicmedia'of the' type described. In processes using paraflinic "oils Tof :the character "mentioned 'a'rato offabout fourzpoundszof the impurities to about '1.75 pounds'rof A-the .oil produces readily `.separable Vt agglomerates.

vThe utilization `of^'-l'rganics of this character.` foraggloineration y'enables a novelfmethod for gtreatin'g the residues. Aaqueous mediumsuch 'oilfwetsz the solid particles 'fIt iis :found thatx in l'an 'ofv elemental sulphur I'preferentially to the disvrthe Vagglorne'ration on the orderiof about 30% of sulphur (dry basis) which may bere- Acovered byiflotationtreatment. The'oil-ag-glom- 'crate .residue Amay @be leached or'fwashed with:

a low jboiling'solvent Ffor vthe oil so as to;v remove theoil. Y The; Y :method may be decolorizedA by any desired y'method, forf'example by treatment rwith 98% the presence f of vhinorganic v-coldescribed rin -copending applisulp'huric acidin `As indicated previously, :the sunique' method` of 'sulphur produced -according jto -fthe :above The molten sulphur yand To this mix there was added.

IWinch-periodithe v s additional j :readily fidrained on l fpersedparticles'ofthegangua As'explained in'- Ythe kearlier. cases referred itc, -r'esidue's 'generally :contain .separating the `sulphur ,from fassociatedimpur- .ities by utilizing speciiicagglomerating` ,reagents -fmay'be :invoked 4to produce .Valuable by-fproducts.

4As `explained incopending lapplication. Serial-No.

384,508, Y Yofi-.colored .sulphur may be fpu'rified ricy utilizing as collecting. .ag'ents;such .materials Vas i .contain a-Areactive Ybasel vvill Vreact lwith the Ysult phuric acid to form a sulphateandsimultanel example, when kaolinite, which is thoroughly dried or partially calcined,v is V.added tov molten,

off-colored sulphur `and 'is agitated with l98% sulphuric acid, Va `Very brilliant canary yellow and exceptionally `iirm ag'- :,glomerates are j for-med from Ywhich the .K molten I -sulphur drains :readily -IIt fappears *treatment a rcertain .quantity of the facid reacts vvvwith both the or-ganicsinv the -zsulphur-and part sulphur is produced that .in this fof the aiummum oxide in the clay kLto.ffprcdiice v65` constituents.

4 ialuminum *sulphate -fandfsilica 'gel. ,--The aluminum sulphate possesses :goodlceme'nting properties and imparts superior firmness to the agi A.gloxnerates vInfurther experimentation with this'type of collecting agent it has been found that reactive 'agents may be employed which serve not only as vcollectors for'i'norganic material in the molten `.bath but which also reactv to produce valuable by-products.

`Of ithis'type'oftreatment that employing raw .org calcined rock or phosphate rock concentrates are` particularly Valuable because the residue produced contains ,available mental sulphur Which-.are advantageous as fertilizers. vIn 1 carrying .out-such fan .aoperation the Y phosphaterocknoriconcentratem y berutilized vto ldecolorize foif -colored sulphur. using .it as a f collecting agent iin a 'smanner agdescribed in fcopending application Serial No. 5384.508. `The sulphuric acid whichf is employed sarytoreact With the tri-icalciurn phosphate to produce the mono and/or di-calcium phosphate plus anamount. of 'free acid sulcientto effect ag- 'glomeration The agglomerates formed may be separated lfrom the molten sulphur and the pelletedm'aterial'may be.-used fdirectly as a fer- '.tilizer. This residue vconstitutes a phosphatecontaining product intheform 'of .firm agglomeratespor pellets of substantially uniform size. This material may `fbe :produced .substantially acid vfree orwithani'excessfof acid. If desired the excess'a'cid'may bei-neutralized 'by treating with -"lime or if additional vfertilizer' components "are desired the neutralization 'may ibe veiected with arnmoni'aca'l materials.

"Within the concept of-theinvention there may lalso be employed other pounds, such 'for example as 'greensand which Vcontain potassium. Under the conditions of the "agglomeration treatment,y -`with sufficient excess UInA vand the residuecomprised of thepellets may be taining available phosphate, may be 'leached and thepotassium sulphate recovered for use in fertilizersor for other purposes.r 4Similarlylthe decolorizing of sulphur may be effected by utilizing` as na collecting agent a mixture 'of ,a phosphate-.containing V.and potassium-,containing `material so 'as to produce a lpurified `suipliur and spherical particles ots'u'bstantially uniform size containing 'assimilable phosphate` and potassium. Y

It will be appreciatedthatjthe above described .method V presents the ,possibility of vrproducing various ytypes of `valuable vfertilizing compositions. For example, ra residue from a ,sulphur decolorizin'gJtreatmnt which -comprises Apellets contain- ,ing available `phosphate fand .elemental sulphur, .with some Afree.acid.,.maybe -mixed with either .tri-calciumrlphosphate.or lgreensand' or other materials containing potentially available fertilizing j tion .to thensoilfthe tree .acidior thefdecomposition lproducts of .,the'nelementalfsulphur is utilizedgto convert thegreensandlor thetri-.c-alcium lphos- A,phatefto aiorm availableifor plant., nutrition.

l of v,the Y methods v ,hereinbeiore describedVV may be :separated rom themoltensulphur in' any .de-v

phosphates and ele-,

minerals, salts lor comusedy as a fertilizer inv-ladmixture with pelletscon-y Again such pelletsV ,'During storage or Aafter -applicaa The -agglomerates Whichrare-"pr'oduced by any;

on even date herewith. Againthe above de# scribed processes may be carried out so as duce substantially uniform sized pellets or spherical units which may be discharged to a simple, screen-bottom container as described in copending application Serial No. 382,845. -Such agglomerates may. be separated from the associated molten sulphur in any other desired manner as for example in arotary drum separator as shown in the drawings.V

-In carrying out .the process the sulphur-containing material to be treated is charged through a line I to the melting tank 2. The material to be treated may comprise, for example a dewatered iiotation concentrate produced from sulphurcontaining ore or any other material whichV is to be treated, such as off-colored sulphur. The melting tank 2 is constructed of suitable corrosion-resistant material and is of a size adequate to fulll the requirements of a particular installation. This may be a squareor. oblong, tank and is preferably provided with one inclined lside set on an angle osf approximatelyp degrees so as to insure proper circulatory motion of the fluids within the container. The container is provided with the steam heating coils 3, the area of which is sufiicient to supply the heat required-to melt the sulphur and, in the case of concentrates-to substantially dehydratev the material. The con-` tainer is provided withthe agita'tingmechanism 4 so as to insure thorough mixing and facilitate` dehydration. In the event the process is to be operated for the production of residues having fertilizer values the phosphate-containing or potassium-containing material may be admitted in a mixture with the sulphur-containingl charge through line I, or may be admitted to tank 2 through the separate charge line I'. vAs will be appreciated, such material may be added to the molten mix in the conditioner 'I in lieu ofthe melting tank '2.

' The container 2 is n connected through the steam jacketed valve 5 steamjacketed line- 6 to 1. Thisrtank is of the and the conditioning tank same'type as tank Zand is provided with `the heating coils 8 and the agitator 9. A v Associated with the conditioningtank 'I is a` source of supply for the agglomerating reagent. This may comprise the tank I0 from which the reagent is fed to the conditioner 'I throughthev line II controlled by valve I2. As described here-.j inbefore, the reagent may comprise a 'mineral' acid, such as a sulphuric or phosphoric acid of re-' quired'strength or other agglomerating reagent, such as a stable mineral oi1 having a boilingpoint above the melting point of sulphur. The a'g glomerating reagent; is added to the molten material in the conditioning tank 'I in the quantitiesY required to form agglomerates olf the desired size ranging from approximately l@ inch to 1/8 inch in diameter in accordance with the principles fully explained in application Serial No. 382,845.` In 'any particular installation a series of twoor moreA conditioning units 'I may be employed.A These may be discharged sequentially so as to insure a substantially continuous operation. f

The material undergoing treatment in conditioner 1 and which.. after treatment,` comprises molten sulphur and associated agglomerated .impurities, is discharged through thesteam jacketed valve I3 and steam jacketed .line I4 to a simple d'rum separator I 5. As shown, thisI separator consists essentially of a reservoir compartment I6 in which the rotating drum I 'I operates. The ro tati-ng 1 drumI is provided with the peripheral to proscreen I8 and is formed with a. partially 'open' side I9. The drum is connected to the driving shaft 20 which is suitably mounted on the compartment I 6. The drum is provided with the angular lifting screens 2 I which serve to continuously skim agglomerated material from the entering charge and to elevate these for discharge. Thel separator is provided with heating means to retain the sulphur in molten condition. This may .take the form of heating coils positioned between the peripheral edge of the screen and the cover together with immersion heaters if desired.

As shown particularly in Figure 2, a residue discharge chute 22 is suitably 'mounted on the base and is adapted to receive the elevated ag# glomerated pellets removed from the bath by the screens -2I.` As shown in Figure 2, ka prededetermined liquid level of molten sulphur is main` tained inthe reservoir as indicated by the dotted line 23. The discharge: line I4, as shown' in Figure 1, is connected to the feed launder 24- so that material to be filtered or separated is dischargedy tary drum separator.

The molten sulphur which drains through the peripheralscreen I8 then overflows through line 25 and passes through the steam jacketed line and is discharged from the system; This product may be passed directly to storage or may be mediately or immediatelyv passed to a unit in which it is decolorized. The solids orresidue' from the drum separator are passed by the chute 22 to the continuous spiral conveyor 3l. This conveyor preferablyv is steamk jacketed. The inclined screw conveyor carries the solids upwardly as indicated by the arrow and such solids are discharged to the container 32. When the collecting material in the from jacketed line Minto the confines of the roif sulphur separation step is a phosphate orsimilar n 40 material the discharged residue may be recovered as such and utilized as a fertilizer ormay be admixed with other fertilizing ingredients in the manner described. When such residue is produced from an agglomeration treatment utilizing oil as the agglomerating medium it may be treated in the manner previously described, so as to effect aseparation and recovery of its contained sulphur. n .50 The free moltenfsulphur adhering to the agglomerates discharged'to the conveyor3| gravitates downwardly infvthe conveyor and are collected in container 33. This' sulphur may be added Ato that discharged through line -3Ill and .'55 subjected tothe same treatment.

It has been found'that when the proper agglomerating reagent is employed and the ratio of reagent to collecting material properly ad,- justed, lagglomerates which are readily separable .60 in the drum separator are produced. Preferably the drum is rotated slowly, i. e. of the order of one-half to one or more R.'P. M. In these cirev cumstances adequate time ispermitted forv draining the moltensulphur 'from the masses of 'ag-y '765 glomerates which are continuously elevated by the lifting screens. The sulphur produced in this mannerjis clear and remarkably free from dispersed gangue; particularly is this true when sulphurcacid is employed asv the agglomeratingi0 reagent in 4amounts .sucientfto produce agglomerated Vparticles of vabout one-eighth vinch in' diameter;` y A charged through line 3 0 does contain some dis-4 i persed gangue i particles these may readily bey "7`5`1ter`e'd out by passing the molten sulphur through In the event that the sulphur dis"-v taining-free sulphur, I andfertilizer materials which comprises treating n the forefto `produce a dewateredflotation concen l trateifthereof; heatingto -themelting .point-zot t sulphur and agitating the-concentrata inthe presence'of insoluble-phosphatesand-a sufficient amountiof sulphuric. acid to solubilize atleast .a l portion ofthephosphate and to agglomerate the treating the resultant 1- glomerationof the available phosphates to vseparate liquid efe-races;

IWaste sulphurecontaining; materiali utilizing aer- ;fe.c.tive.;and'inexpensive agents.; In certain-.circumstancesthe-reagent; employed: mayf be yuti'. llized Lato; subservethe; additional; advantage, of; reacting.; with the .collecting material to: :produce reaction products of considerable value Whilesubservingf; the. mainlafunction roff: ,purifying su1phur. While preferredy embodiments- `have-:been.described it-.isftof be `understood that of-:the y invention these are given Ididacticallyy 19o-"illustrate,the-fun-r damental principles; involved tand not. as indicating any exclusive method or 'any restricted .group (of reagents employable undenthe invention.

- We claim: n n v .1. A 1r 1et"nod=.-ofr Vtreatingsulphur ore-s, conto recover-agpurified sulphur phosphate and .gangue lof the orefinto rm,.self.

sustaining 4spheroidal agglomerates of from-approximately 1/{34 inch-tol/g inch` in diameter,

` mass.v to separate liquid puriiiedsulphur and nodulated material having avoidable fertilizing value..`

Y 2.,.A methodof treating sulphur ores, Containf ing` free sulphur,

sulphur, heating to the' melting point of 'sulphur andagitating the concentrate in the presence of material containing tri-calcium phosphate and a sufficient amount of sulphuric acid to convert the tri-calcium phosphate to available phosphate, the acid being in'suicient 'excess to effect agdividually distinct nodular masses. v

. to recover a puriied sulphur VYand fertilizer materials which comprises treating the 'ore to producea concentrate enriched in` into in- '3.' Ainethod of treating sulphur'ores, con'tain.l y

ingf'free sulphur, to Vobtainsa:purified sulphur and fertilizer materialrwhich self-sustaining spheroidal agglomerates of at least 1/54 inch in diameter,'treating the resulting vmass;

`puried sulphur anda nodulated fertilizer; material containing available Apo. tassium. v

4. A method ofv treating sulphur ores, containing freeL sulphunzto obtain apurified sulphurA and fertilizer material which:comprisestreating the1-,.oreto produce aconcentrate enrichedvin sulphur,Y heating at least-tothe melting point of sulphur andv agitatingvv the concentrate,V in the presence yoflzmaterial.'.containingl insoluble potes:Y

comprises vtreating the;v ore'toproduce a concentrate enrichedin sulphur,-

sium 3. compounds:y together; with azi. sufcient amount of` sulphuric acidi. toy solubilize: .at leas-t. aar-portion ofi.; the potassium compoundazandstov agglomerate Vsuch compound .and .the ganguefof. the Aore .into rm, self-sustaining-spheroidalaage glomerates of fromapproximatelyv l/eeinchcto' 1/2 inch in diametentreating the resultingmass to recover a Y purified sulphur :and a nodulated .fertilizer ,material lcontaining;available,v potassf sium and elemental sulphur'.A

5. A methodf oftreating sulphur oresccntaining free sulphurf to recover. apuried: sulphur. andfertilizer materials; which.. comprises, treats) ing the. ore to produce a dewateredilotation' concentrate thereof, heatingy at; least to, themelt; ingpoint ofsulphur and agitating ,theconcena trate in the; presence of insoluble".` potassium compoundsv and a suicient amount; of'sulphurc acid: ,tov solubilizezatgleast a portionfof the-come l poundzand to agglomeratasuch compoundgand' the. gangue tofxthek ore .into irm,.self-sustaining agglomerates of.V at least .1/s4inch 1in; diameter;` treatingithe. resulting'mtss` to separater liquid puri'ed sulphur and' aY nodulated lmaterial: having a fertilizer value.l

6. A method of treating olf-"coloredzfree "sul' phr to decolorize such sulphur andurecover valuable by-products kwhich comprisesJ agitatingthe sulphur in molten condition in thel presencev of r'a predetermined quantity of insoluble phos-A phaterand a sufli'cient amount: of sulphuric acid tasciubilize at least' a'portion ofthe phosphate and to agglomeratethe'phosphate andfgangu'e ofthe ore into rm, self-sustaining spheroidalparticles of from Vapproximately 1/64 inch to 1% inch in diameter andftreatingthe resulting massl to separate and recover a decolorized sulphur and'n'od'ulated material having-a fertilizer value:

'7; A method of treating onf-colored free sul-J phurf' to decolorize such sulphur and recover valuable by-products which comprises'agitating the sulphur in molten condition, in the presence of a predetermined `quantity of insoluble'phosephate and a sufficient amount of 98% sulphuric acid to solubilize at least a portion of the phos; phateand to agglomerate the. phosphateand gangue of the ore into. firm, self-sustaining, spheroidal particles of from approximately l/ci: inch to 1/a inch in diameterandl treating the resulting mass jto separate. and recover. a decolorfertilizer value.

8'. A A,I'nethod v of treating sulphur ores containr` ing-free sulphur, to obtain a puriedl-sulphurand a fertilizer material Whichcomprisesv treating thevv ore to. produce arconcentrate enriched in sulphur, heatingrat least to the melting point of ,sulphurv and agitating theconcentrate inthe presence. of a Vmaterial containing an.- insoluble. compound having a potential fertilizer value, chosenf from thegroup consistingof insoluble phosphateand insoluble .v potassiumcompounds together; With-- a vrsucient amount of sulphuricV acid.V to. solubilize at least afportion. of the saidinsoluble compoundv and to agglomeratefsuchcompounde and the sangue of the ore.- intoermgspherodial.agglomerates offrom-vapproximately 1/64inch .to :1/2l inch indiameter, treating-the resulting-masstosep-fL r aratea Y'purified sulphur andanodulatedgirla-4 terialzcontaining available. fertilizer values.

9. A. method of treatin-g vsulphurA ores.,K contains. ing; free sulphur., to. .recover af. Apurified ,sulphur and .fertilizer materialsing. :the ore to produce v-aconcentrate..enrichediin sulphur, heating to the melting point of sulphur and agitating the concentrate in the presence of a. material containing trcalcium phosphate and a, sufficient amount of sulphuric acid to` convert thevtricalcium' phosphate to available phosphate, the acid being in sulcient excess to effect agglomeration of the available phosphate and the gangue into `.individually distinct nodular masses of fromapproximately 1/64 inch to 1A; inch in diameter. ARTHUR B. MENEFEE. HERBERT H. GREGER.

The fol REFERENCES CITED lowing references are of record in the le of this patent:

Number UNITED STATES PATENTS Name t Date Perry June 5, 1923 Guernsey Feb. 12, 1935 Schwab Jan. 17, 1928 Gilbert June 6, 1939 Hardesty et a1. June 23, 1942 

